HYPER lab member Ian Richardson recently finished recreating the methane-ethane-nitrogen seas on Saturn’s moon Titan. Titan, the second largest moon in the solar system, is the only other body besides Earth known to have liquid seas or oceans on it’s surface. For scale, Titan is about half the diameter of Earth — Titanic! A recent picture from Cassini and corresponding article from space.com highlight the chances for new forms of life existing on Titan.

Ian worked with Jason Hartwig at NASA-Glenn as part of his NASA Space Technology Research Fellowship to create the conditions necessary to take pressure-density-temperature-composition, effervescence, and freezing-liquid measurements. These measurements will aid the design of a submarine mission to Titan around 2032.

The ternary (3 part) mixture measurements were a challenge — the solubility of nitrogen changes substantially based on the methane-ethane composition. It’s similar to the problem of carbon dioxide dissolved in soda pop, but at -288°F or 95 K.

Effervescence measurements are needed to determine if the radioisotope thermoelectric generator powerplant in the submarine will generate too many nitrogen bubbles from heat rejection. These bubbles could destabilize the sub or obstruct camera shots. To take these measurements we had to engineer a fiber-optic boroscope that could penetrate the walls of our cryostat and withstand the pressurized cryogenic environment. We succeeded and Ian was able to make the following videos of ethane-methane rain and snow.

Ian will present the results at the Cryogenics Engineering Conference in two weeks before defending his Dissertation the end of July.

I walked into the lab the other day and Ian swished a shot through the Nerf basketball hoop over the door. Carl Bunge yelled out: “Ian’s making it rain!” Yes he is Carl and it’s out of this world!

While conducting composition measurements on helium-hydrogen mixtures using a Varian gas chromatograph at WSU’s Analytical Chemistry Service Center, I discovered that the ratio of orthohydrogen–parahydrogen has a significant effect on the measurements. An in depth discussion of the allotropic forms of hydrogen can be found in the previous post “Why equilibrium hydrogen doesn’t exist”. In my system, gaseous hydrogen is condensed in a copper test cell at 20 K. An ortho-para catalyst is placed in the bottom of the test cell to ensure all of the hydrogen is converted to parahydrogen. Helium gas is then introduced into the test cell to the desired pressure. The amount of helium that dissolves into the liquid is measured by extracting a liquid sample through a tube at the bottom of the test cell where it is vaporized and collected in a gas sampling bag. The composition of the sample is then analyzed using gas chromatography. The total composition of the first helium-hydrogen measurements were only totaling between 80% – 90% instead of the expected 100%. The GC column was packed with a hydrogen compatible material so it was unlikely the equipment was causing the discrepancy. We double checked that the primary standard gas mixtures were still obtaining correct measurements, they were. The only difference was that the gas standards contained normal hydrogen (since they were maintained at room temperature) and the samples being collected were parahydrogen. By adding an ortho-para catalyst just before the mixture was collected in the sampling bag, I was able to convert the hydrogen back to the normal composition. After this was implemented, every gas sample measurement was within the uncertainty of the equipment. Once again, the subtle differences between orthohydrogen and parahydrogen cannot be overlooked even in a process as standardized as gas chromatography.

To go along with the other Toyota Mirai post, I was wandering around Tokyo on Wednesday and stumbled across the Toyota showroom. They had a Mirai and labelled chassis on display as well as demo hydrogen fueling nozzles.